Human Anatomy and Physiology I, Frolich, Brainstem

Brain Tidbit II: Brainstem

• Medulla oblongata

• Pons

• Mesencephalon (midbrain)

Human Anatomy and Physiology I, Frolich, Brainstem

What is brainstem?

• Interior inferior “core” of brain

• Includes all parts of brain except:– Cerebral hemispheres– Cerebellum– Diencephalon– (remember “2-oval skull”)

• Think direct autonomic control

“2-oval skull”(brainstem deep and inferior)

Cerebral hemispheres

Cerebellum

Human Anatomy and Physiology I, Frolich, Brainstem

Medulla oblongata(relay from the spinal cord)

What is it?• Extension of spinal cord

into cranial cavity• All motor and sensory

information to and from peripheral nerves via spinal cord passes through

• Central canal of spinal cord opens into fourth ventricle

What it does?• Autonomic nuclei control

visceral activity– Cardio-vascular: heart

rate, strength of heart contractions, vasomotor (blood vessel opening)

• Respiratory rhythmicity center

• Nuclei for Cranial Nerves VIII-XII

• Relay for sensory and motor information to other brain regions

Human Anatomy and Physiology I, Frolich, Brainstem

Human Anatomy and Physiology I, Frolich, Brainstem

Pons (relay from “lower” to “higher” functions)

• Links higher to lower brain region• Nuclei for Cranial Nerves V-VIII• Nuclei that control respiration• Part of “metencephalon”

Human Anatomy and Physiology I, Frolich, Brainstem

Midbrain/Mesencephalon(integration of information for reflexive movements)

• Superior to pons

• Deep within brain

• Superior and inferior colliculi—initiate reflexive responses to visual and auditory input

• Substantia nigra and red nuclei (basal ganglia)—background skeletal muscle tone

• Nuclei for Cranial Nerves III, IV

Human Anatomy and Physiology I, Frolich, Brainstem

Human Anatomy and Physiology I, Frolich, Brainstem

Interactive overview of basic regions of brain from PBS

[link]